Sleep apnea (SA) is a disease state in which the patient exhibits periodic breathing. Sleep apnea is typically characterized as either “obstructive” (OSA) or “central” (CSA). Many patients exhibit the disorder in both of its forms, OSA and CSA. OSA is traditionally treated by attempting to maintain patency of the upper airway. CSA is traditionally treated by stimulation of the diaphragm. Sleep apneas occur with high frequency in patients with cardiac rhythm disorders that might be treated with bradycardia treatment or biventricular pacemakers.